1. Field of the Invention
This invention relates to ethylenically unsaturated polymerizable monomers which are particularly suitable for use as wet adhesion promoters. More specifically, the polymerizable monomers of the present invention are useful to promote adhesion in polymers and copolymers, and especially in aqueous emulsion copolymer latices which are used to prepare latex paints.
2. Description of Related Art
The term "wet adhesion" is used in the paint industry to describe the ability of a paint to retain its adhesive bond to a substrate under wet or high humidity conditions. While oil-based systems are known to retain their adhesive properties under wet or humid conditions, the tendency of many water based coatings (i.e., latices) to lose their adhesive properties when wet has limited the usefulness of such coatings. The wet adhesion deficiency of latex paints also makes surfaces painted with such paints less scrub resistant than those surfaces painted with organic solvent based paints. See S. M. Kabanis and G. Chip, "Polymer and Paint Properties Affecting Wet Adhesion," Journal of Coatings Technology, 53(682), 57-64 (November 1981).
Since the use of water-based emulsion polymer systems as protective and decorative coatings for many types of surfaces has become widespread, such systems being used by individuals in homes and in industry, there is a great need for improved wet adhesion of such systems. In recent years, the art has recognized the problem of loss of adhesive properties in latex paints and a variety of additives to latex systems to improve wet adhesion have been proposed. Incorporation of amine, amide and acetoacetate functionalities into latex polymers has been reported to improve the wet adhesion properties of latex paints. A number of publications also describe the use of urea and ureido-functional monomers for such purpose. See, for example, U.S. Pat. No. 2,72,7016, U.S. Pat. No. 2,727,019, U.S. Pat. No. 2,881,171, U.S. Pat. No. 2,980,652, U.S. Pat. No. 3,194,792, U.S. Pat. No. 3,356,654, U.S. Pat. No. 3,369,008, U.S. Pat. No. 3,509,085, U.S. Pat. No. 4,104,220, U.S. Pat. No. 4,111,877, U.S. Pat. No. 4,219,454, U.S. Pat. No. 4,314,067, U.S. Pat. No. 4,319,032, U.S. Pat. No. 4,426,503, U.S. Pat. No. 4,596,850, U.S. Pat. No. 4,599,417, U.S. Pat. No. 4,617,364, U.S. Pat. No. 4,622,374, U.S. Pat. No. 4,730,045, U.S. Pat. No. 4,766,221, U.S. Pat. No. 4,770,668, U.S. Pat. No. 4,777,265, U.S. Pat. No. 4,783,539, U.S. Pat. No. 4,883,873, U.S. Pat. No. 5,210,199, U.S. Pat. No. 5,498,723, U.S. Pat. No. 5,567,826, U.S. Pat. No. 5,610,313 and WO91/12243, all of which are incorporated by reference herein for all purposes as if fully set forth.
A number of these known urealureido functional monomers, however, have provided unsatisfactory wet adhesion results. Many may also be very expensive and their inclusion into latex polymers results in a substantial increase in the cost of the vinyl, vinyl-acrylic and all-acrylic polymers used in latex-based paints.
It has now been discovered that excellent wet adhesion properties can be imparted into aqueous emulsion systems used to make latex paints by incorporating into the monomer system, from which the polymer is produced, a new class of urea/ureido functional polymerizable monomers including cyclic urea moieties derived from alkyleneureas, hydroxyalkylalkyleneureas, aminoalkylalkyleneureas and their Diels-Alder adducts with 1,3-dienes.
Latex-containing surface coatings and coating compositions having superior wet adhesion properties may therefore be produced by including in the monomer system one or a mixture of the monomers of the present invention. In particular the monomers of this invention have been found to be especially useful in water-based latex-containing paints.